Soften gelatin in cold water. Beat 4 egg yolks until frothy. Add maple syrup. Mix well. Add gelatin. Pour into saucepan. Let cook over very low heat, stirring constantly, for about 10 min. (Should be quite thick). Cool. Beat egg whites; add cream of tartar and beat until stiff peaks form. Fold together gelatin mixture, egg whites, and whipped cream. Spoon into dessert dishes and serve. May be sprinkled with nuts if desired.